Printing devices



April 4, 1967 J. P. sEBRlNG PRINTING DEVICESl Filed Feb. 4. 196e M W j mINVENTOR. n Jfa 2.7156575@ LL/f 41g 6%@ Waff/493 United States Patentfice 3,312,164 Patented Apr. 4, 1967 3,312,164 PRINTING DEVICES John P.Sebring, Lewiston, NY., assigner to Moore Business Forms, Inc., NiagaraFalls, NIY., a corporation of Delaware Filed Feb. 4, 1966, Ser. No.525,074 8 Claims. (Cl. lill- 93) This invention relates to printingdevices and more particularly to such devices wherein the impression onthe sheet is made by causing a hammer to strike the reverse side of thepaper or other medium and force the immediate area of the front surfacethereof against a type face.

This particular printing device probably finds its most important use incomputer machines, where a print-out is made on a continuous multiplepart form. In many of these machines the imprinting is made against atype chain carrying a complete font of type. Such a chain is moved toand fro selectively so that the proper character is placed into printingposition, and then the impression is made by the print hammer strikingthrough the multiple part form from the rear surface thereof.

However, it has been found, particularly in the case of the last fewcarbon impressions in a multiple form, that a shadow or halo appearsaround the impressed figure or number. This phenomenon is caused by theaction ofthe hammer which appears to mold at least the rearward layersof the multiple form around the edges of the hammer, due to the partialembedment of the hammer element in the multiple relatively soft oryielding form pack. Us ually the halo or shadow appears only on the lastfew elements of the multiple form but obviously this constitutes adisadvantage and drawback in this kind of printing.

It is therefore a principal object of the present invention to providemeans for use in printing apparatus of the class described foreliminating such undesirable shadow or halo impressions.

The present invention results from the discovery that such defects canbe eliminated by the interposition of a particular kind of shieldbetween the print hammer and the back of the form. This shield is oflaminar form and is made of multiple layers of thin plastic material andthe invention contemplates the provision broadly of a range of layers ofthe material and thicknesses within which the desired result becomesappreciable, and also the provision of optimum laminar and thicknessqualifications for the maximum results.

More specifically, the invention contemplates .the provision of alaminar shield or pack comprised of multiple layers of Mylar plastic.Mylar is a trademark distinguish ing a polyester film materialmanufactured by'E. I. du Pont de Nemours & Co., the material beingpolyethylene terephthalate, which is a polymer formed by thecondensation reaction of ethylene glycol and terephthalic acid. Thismaterial will be further defined by its known properties in the presentspecification.

The invention thus embraces an impact printing machine of the kinddescribed employing this novel and improved shield, and also includesthe multiple layer shield as an article of manufacture.

Other objects and features of novelty will be apparent from thefollowing specification when read in connection with the accompanyingdrawings in which one embodiment of the invention is illustrated by wayof example.

In the drawings:

FIGURES 1 and 2 are diagrammatic views,l not drawn to scale, showingrespectively prior art arrangements with the parts in position prior toand during impact bythe hammer;

FIGURES 3 and 4 are views similar to FIGURES l and 2 respectively andillustrative of the two corresponding stages with the use of the novelshield forming an essential element of the present invention;

FIGURE 5 is a fragmentary view suggesting one way of securing the novelshield to the nose frame of a printing apparatus and in front of thehammers;

FIGURE 6 is an enlarged fragmentary view showing the preferred structureof the plastic shield;

FIGURE 7 is a fragmentary View illustrating as Well as possible,considering the limitations of drawing, the undesirable halos or shadowswhich prevail in the impact printing machines now in use; and

FIGURE 8 is a similar View illustrating the freedom from shadow or haloon a record sheet nearest the hammer in a device following theprinciples of the present invention.

In the generic and quite diagrammatic showings in FIGURES l and 2, theprior art developments along this line of printing are exemplied. At 10in these figures there is indicated a type element representative ofnumerous prior art constructions, whether carried upon a rotatablecylinder or arranged in the form of a chain. The character comprisingletters, numbers, or punctuation marks is of course embossed orotherwise delineated upon the face of the type member 10 as at 12.

Similarly illustrated in diagrammatic fashion is a ribbon which can bemoved step-by-step across the face 12 of the type 1() by suitableactuation of the reels 16 and 17 upon which the ribbon is wound.

A projectable hammer member 20 of which there may be any desired numberselectively actuated, is mounted for delivering an impact against therear surface of the sheet or manifold pack which passes between thehammer and the type and ribbon set-up. Such a manifold pack isillustrated, for example, at in these figures of drawing and will beseen to comprise in the illustrated example, four record sheets a andthree interposed carbon or transfer sheets b.

Thus as used in the claims, the term sheet.of record material or thelike shall mean a single layer vora multi-layer pack. i Now in thenormal operation of currently used-devices of this character, asillustrated in FIGURES 1 and 2, the hammer 20 in delivering its blowstrikes the rear surface of the pack 25 and forces it against theportion of the ribbon 15 which overlies the type face 12 of the typeelement 10. As shown in possibly somewhat exaggerated form due to thenecessary enlargement of the thickness of the pack for illustrativepurposes, the face 21 of the hammer compresses the sheets a and b andembeds itself slightly within the rear surface of the pack r causing therearmost sheets to wraparound the margins of the hammer face 21 and thuscause the carbon or transfer coating to frame the character impressionwith a rough irregularly imprinted shadow or halo. This undesirableframing of the character is suggested in FIGURE 7 of the drawings and itoccurs definitely on the rearmost record sheet a and frequently onseveral of the rearward sheets.

As mentioned in the presentation of the objects of the presentinvention, applicant has provided a buffer strip which is interposedbetween the face 21 of the hammer 20 and the rearmost record sheet a ofthe pack 25. This guard strip or shield is diagrammatically illustratedat 30 in FIGURESG and 4 of the drawings. The idle position of thevarious parts is suggested in FIGURE 3 Iand the positions shown inFIGURE 4 are diagrammatically illustrative of the effect upon impact ofthe hammer upon the rear face of the guard or shield 30 whichlies'against the manifold pack 25. I i

The impact of the hammer is absorbed by the shield strip 30 and seems tobroaden out the force of impact of the hammer so that the rearwardportions of the multiple form do not mold themselves around the Ihammerface, but the hammer Astill transmits enough pressure to makesummarizing these results, the following delineations appear. Thedescribed improvement begins to make itself appreciable in the case ofeach material, with two layers of tilm each of a thickness of 0.0035inch-total thickness 0.007 inch; two layers of film each of a thicknessof D a good impression, such as suggested in FIGURE S of .005 inch-totalthickness 0.010 inch, and six layers of the drawings. film each of athickness of .0015 inch--total thickness Experimentation has shown thatthis novel and beneii- 0.090 inch. It can be said then that with respectto all cial effect is limited to some extent by the thickness of laminarthicknesses any total of over 0.011 inch or -a total the individualsheets comprising the guard strip, the 10 of below 0.007 inch, givespoor results. Also, it has been number f sheets employed, and theplastic material of determined that individual Single Sheets 0f morethan which the sheets are made. 0.005 inc-h of thickness are not usable.

Before going into these somewhat critical data, it would Finally, theoptimum results superior to any other combe well to show an example ofone install-ation of the binations have been found to be the use ofseven laminaguard sheet in relation to the hammers. In FIGURE 6 15 tionsof nlm of 0.0015 inch of thickness, giving a total of the drawings atypical pack or laminar shield is illusthickness of 0.0105 inch. tratedin somewhat diagrammatic exaggerated form. The Thus it may be statedthat the effective total thickness pack comprises outer sheets A and Band inner sheets C lies Within the approximate range of 0.007 inch to0.0105 which are embraced between the outer sheets. In order inch. toprovide a convenient envelope for holding the lamina- 20 It isunderstood that thepresent invention is applicable tions together, theend sheets A and B are somewhat to a wide variety of impact hammerprinting devices wider than the intermediate sheets C and the protrudingand that the machines illustrated and described diagramedges D may besecured together adhesively or otherwise, matically herein are forgeneric illustration only. Also, for example, by means of a strip ofdouble-face `adhesive various changes and modifications may be made inthe tape suggested at D. 25 embodiments disclosed without departing fromthe scope -In FIGURE there is illustrated one form of hammer of theinvention as determined by the subjoined claims. enclosure, sometimesreferred to as a nose cone. This Having thus described the invention,what is claimed casing iS indicated nl 50 'and cOmPriSeS a freni face51, as new and desired to be secured by Letters Patent is:

a p panel 52, end Wall 53, and attaching flange 54. 1. Printingapparatus comprising a type member hav- Along the width of the enclosure50 is provided an elon- 30 ing a surface formed to present a typecharacter, means gated Slot 50 ihrOllgh Which a multiplicity 0f hammersfor supporting a sheet of record material with its surface are adaptedto be projected. to be printed presented in front of said type surface,

The laminar Shield 0r buffer Pack 30 may he Secured hammer means fordelivering a blow to the rear surface acrOSS the face 51 0f the frame 5021S indicated in FIC of said record material to force the front faceagainst URE 5, the ilange Portion D'Of the Peck being Secured 35 saidtype surface to imprint a character thereon, laminar O the member in anySuitable fashion 3S Suggested means supported in front of said hammerand between at 55- the hammer and the rear surface of said record sheetto It has been determined by eXPcrimenmliOn that thc sustain the directforce of the hammer blow and eliminate desired result is attained by theuse of multiple sheets the production of a halo or Shadow imagebordering the 0f Polyester PlaSic material made from Polyethylene 40character reproduced on the record sheet, said laminar terephihnlaie,Ithe Polymer formed hy the condensation means comprising multiple layersof thin plastic sheeting, reaction of ethylene glycol and terephthalicacid. Thls Said plastic sheeting being a polyester mm made from material1s manufactured 'by E. I. du Pont de Nemours& polyethyleneterephthalate, the Polymer formed by the C0' under. the trademark Mylar'Ideritfyllg properiles condensation reaction of ethylene glycol andterephthalic of theD preferred fom off 1l/Iylar fir use 1n thilsapplicatilon 45 acid may e enumerate as o ows: u timate tensi e strengt40,000 p.s.i.; stress to produce 5% elongation-21,000 to 1.12 hThehapalrlatui 'asfsetlforth m dun? 1 in Whlch the 25,000 p.s.i.; ultimateelongation-50%; tensile moduim ast e o owing Urt 1er Properties ltlmatetnslle lusf 800,000 plsj.; impact Strength 6'0 kgrcmjmil;strength-40,000 psi.; stress to produce 5 ,a elongationdensity-1.37grams/Cc.; coeicient of friction (kinetic) 50 21,090 to 25,000 PS-19ultimate mignon-50%? tensile (film-to-ilm) 0.38; melting point, 250 to265 C. modulus-800,000 p.s.1.; density-1.377; and coeticient With regardto the thickness `of the individual lamina- 0f friction (kinetic)(lm0lm)-038- tions and the number of laminations employed, it is inter-3- The apparatus aS Sei forth in Claim 1 in Which the esting to note thefollowing results of experiments: laminar means comprises a pack of fromtwo to seven Number oi Laminations Total No Change Slight ConsiderableMaximum Thickness Improvement Improvement Results Lamlnation thickness,

5 layers of film of from 0.0015 inch to 0.005 inch of thickness of eachlayer.

4. The apparatus as set forth in claim 1 in which the laminar means hasa total thickness of from about 0.0070 inch to about 0.0105 inch.

5. The apparatus as set forth in claim 1 in which the total thickness ofthe laminar means is approximately 0.0105 inch.

6. The apparatus as set forth in claim 1 in which the laminar vmeanscomprises seven layers of film each layer about 0.0015 inch thick.

7. Printing apparatus comprising a type member having a surface formedto present a type character, means for supporting a sheet of recordmaterial with its surface to be printed presented in front of said typesurface, hammer means for delivering a blow to the rear surface of saidrecord material to force the front face against said type surface toimprint a character thereon, laminar means supported in front of saidhammer and between the hammer and the rear surface of said record sheetto sustain the direct force of the hammer blow and eliminate theproduction of a halo or shadow image bordering the character reproducedon the record sheet, said laminar means comprising multiple layers ofthin plastic sheeting, said laminar means comprising at least threelayers, the inner and outer layers being somewhat Wider than theintervening layers and the extended portions of said inner and outerlayers being secured together thus providing yan envelope for saidintervening layers.

8. As an article of manufacture for use in an impact printing devicewherein hammers are employed to strike the rear face of record sheetingto force the forward face thereof against xed type for effecting animpression', a buffer strip for insertion between said hammers and therecord sheeting, said buffer strip comprising from about three to aboutseven layers of polyester lm made from polyethylene terephthalate, thepolymer formed by the condensation reaction of ethylene glycol andterephthalic acid, the innermost and outermost layers being somewhatwider than the intervening layers and the extended portions of saidinner and outer layers being secured together thus forming -an envelopefor containing said intervening layers.

References Cited by the Examiner UNITED STATES PATENTS 168,373 10/1875Chipman 161--99 1,939,306 12/1933 Leslie 161--99 2,584,092 1/1952 Kelleret al. lOl-38 3,090,297 5/1963 Wilkins et al. 101--93 3,143,063 8/1964Stark 101--93 ROBERT E. PULFREY, Primary Examiner.

W. F. MCCARTHY, Assistant Examiner.

1. PRINTING APPARATUS COMPRISING ATYPE MEMBER HAVING A SURFACE FORMED TOPRESENT A TYPE CHARACTER, MEANS FOR SUPPORTING A SHEET OF RECORDMATERIAL WITH ITS SURFACE TO BE PRINTED PRESENTED IN FRONT OF SAID TYPESURFACE, HAMMER MEANS FOR DELIVERING A BLOW TO THE REAR SURFACE OF SAIDRECORD MATERIAL TO FORCE THE FRONT FACE AGAINST SAID TYPE SURFACE TOIMPRINT A CHARACTER THEREON, LAMINAR MEANS SUPPORTED IN FRONT OF SAIDHAMMER AND BETWEEN THE HAMMER AND THE REAR SURFACE OF SAID RECORD SHEETTO SUSTAIN THE DIRECT FORCE OF THE HAMMER BLOW AND ELIMINATE THEPRODUCTION OF A HALO OR SHADOW IMAGE BORDERING THE CHARACTER REPRODUCEDON THE RECORD SHEET, SAID LAMINAR